45°
The sun angle problem
Your skin makes the vitamin only when the sun's rays are more than 45 degrees above the horizon. If your shadow is longer than your height, the atmosphere blocks the right rays and there's no synthesis.
How to take vitamin D3 properly and where to order it from iHerb
If you ask a doctor which supplement almost everyone at our latitudes should take, the answer is always the same: vitamin D3. It supports strong bones and teeth, morning energy, immunity and a steady mood when the sky outside is gray for half the year.
Types of vitamin D
On the shelves of pharmacies and marketplaces you'll find D2, D3, drops, capsules and gummies. Here's the real difference.
D2, ergocalciferol
A plant-based form made from yeast and mushrooms. The body absorbs it poorly and reluctantly, and today this form is considered outdated.
D3, cholecalciferol
The natural form, identical to the one your skin produces in the sun. It's absorbed faster, raises blood levels more reliably and holds the result longer.
Why K2 is added
K2 pulls excess calcium out of the blood vessels and directs it to bones and tooth enamel. Up to 2000 IU, plain D3 is enough; at higher doses it's better to take a D3 + K2 combo.
Forms: what's easier to take
Each age has its own form. Here's how they differ.
Oil-based capsules
For adults. Vitamin D is fat-soluble: in a capsule it's already dissolved in olive or coconut oil and ready to be absorbed right away. Very convenient!
Oil-based drops
For babies. Good drops contain only coconut, olive or another natural oil plus the vitamin itself: no sugar, preservatives or allergens.
Water-based drops
Often sold in regular pharmacies. The vitamin is made to mix with water using alcohol, preservatives and flavorings: many kids get a rash or a stomachache from such formulas.
Chewable lozenges
From age 3-4. A solution for kids who spit out drops and choke on capsules. It's best to keep the jar up high so your child doesn't eat the whole thing.
Why in the mid-latitudes
everyone needs vitamin D
Unless you live in the tropics year-round, you can't get vitamin D naturally.
11:30-15:30
A short window of sun
The right kind of sun only comes from late May to mid-August, strictly around midday. From October to May, even on a clear frosty day, synthesis is zero.
98%
Tanning and sunscreen won't help
The darker your skin gets, the less vitamin it produces. Sunscreen with SPF 15 or higher blocks 98 percent of vitamin D production.
You can't stock up over the summer. Your body uses up its vitamin D reserves in about 3-4 weeks. What you stored up on a beach vacation is guaranteed not to last even until the November holidays. That's why doctors agree: in the mid-latitudes, vitamin D should be taken either year-round without breaks, or at least from September to May.
How D3 deficiency drains your energy
A lack of vitamin D3 lowers your energy level: this vitamin plays a part in the work of mitochondria (the cells' power stations), in maintaining muscle strength and in regulating mood.
Impaired mitochondrial function
Vitamin D3 helps cells produce ATP molecules, the main source of energy. Without enough of it, mitochondria work less efficiently.
Muscle weakness and pain
A deficiency disrupts calcium and phosphorus metabolism, leading to muscle weakness, quick fatigue during exercise and pain.
Low mood and apathy
A lack of the sunshine vitamin affects the production of feel-good hormones (serotonin and dopamine), causing drowsiness, anxiety and low spirits.
Chronic fatigue
According to Cleveland Clinic, constant fatigue and low energy are among the main signs of vitamin D deficiency.
How to take vitamin D the right way
Three simple rules to make sure the supplement actually works for you.
01Take it in the morning or at lunch
Vitamin D gives the nervous system a slight boost and suppresses the production of melatonin, the sleep hormone. Taking it at night can lead to insomnia.
02Always with a meal that contains fats
Eggs, a sandwich with butter or cheese, avocado, porridge with milk, a handful of nuts: with food like this, the vitamin is fully absorbed. Taking it on an empty stomach is pointless.
03Don't chase high doses without a test
The safe dose for an adult without testing is 2000 IU per day. If you suspect a deficiency, get a 25-OH vitamin D blood test. If your level is below 20-30 ng/mL, a doctor may prescribe 5000-10,000 IU for 1-2 months.
Dosage by age
Preventive regimens, daily dose
0-12 months400-1000 IU
1-3 years1000-1500 IU
3-18 years1000-2000 IU
Adults, prevention2000 IU
Adults with deficiency5000 IU as a courseInfants definitely need the supplement: breast milk contains very little vitamin D. For adults with a deficiency, it's 5000 IU for a couple of months, then switching to 2000 IU.
Delivery from the USA
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Special price for delivering vitamins from the USA with Prostobox
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5-10 dayshome delivery
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$29.90 / 3 kgiHerb rate
Prostobox × iHerb
How to order
How to order
vitamin D3
from iHerb
D3
From sign-up to a parcel at a convenient pickup point.
2
Buy on iHerb or place an order with our buyers
Place an order to our address, or send us the links and we'll buy the order for you. With the promo code GETIHERB, the buyout is free.
3
Receive your parcel
We'll deliver it in 5-10 days to a convenient pickup point. Pay in rubles, dollars or cryptocurrency, your choice.
Trusted vitamin D3 from iHerb
The best vitamins from iHerb, with clean ingredients, transparent dosages and a good price-to-quantity ratio.
Basic prevention for adults (1000-2200 IU)
A daily maintenance dose for prevention in temperate climates, where sunlight is scarce for most of the year. Suitable for regular use without a doctor's prescription.
California Gold Nutrition
Vitamin D3, 2000 IU, 360 capsules
$12.63
The platform's bestseller: a convenient fish gelatin shell and a tiny capsule that goes down easily. A solid foundation for keeping vitamin D levels steady in temperate climates.
Help with your purchase →
NOW Foods
Vitamin D3, 2000 IU, 120 capsules
$5.18
A classic budget-friendly choice made to GMP standards. The olive oil base protects cholecalciferol from oxidation and ensures high absorption even with a light breakfast.
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Doctor's Best
Vitamin D3, 2000 IU, 180 capsules
$9.99
A supplement from a California brand focused on evidence-based nutraceuticals. GMO-free and gluten-free formula, stable in storage. The capsules are smooth and small, ideal if you don't like large pills.
Help with your purchase →
Solgar
Vitamin D3, 2200 IU, 100 vegetarian capsules
$12.56
A premium line in amber glass that protects against UV light. A fully vegetarian formula with no animal gelatin. Take the dry capsule with a hearty meal that contains fats.
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Nature Made
Vitamin D3, 2000 IU, 250 capsules
$17.20
A USP Verified brand: the composition, raw material purity and dosage accuracy are confirmed by an independent laboratory. A reliable basis for adult prevention, with plenty of supply in the bottle.
Help with your purchase →
Bluebonnet Nutrition
Liquid vitamin D3 drops, citrus, 2000 IU, 30 ml
$20.76
A solution for adults who find it hard to swallow capsules. The liquid triglyceride-based form with a light citrus scent is easy to dose and absorbs quickly. One bottle lasts a couple of seasons.
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NOW Foods
High-potency vitamin D3, 2000 IU, 240 capsules
$8.83
A large 240-capsule pack made to GMP standards. The oil base ensures good cholecalciferol absorption, and the pack lasts a whole season.
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California Gold Nutrition
Vitamin D3, 2000 IU, 90 capsules
$4.92
A compact pack of the platform's bestseller. Tiny fish gelatin capsules are easy to swallow, a budget-friendly everyday basic.
Help with your purchase →Therapeutic doses (5000-10,000 IU) for deficiency
High doses for a course to restore vitamin D levels when a deficiency is confirmed by tests. Taken for a limited time, as prescribed and under a doctor's supervision.
NOW Foods
High-potency vitamin D3, 5000 IU, 240 capsules
$12.92
A supplement for quickly correcting a deficiency as prescribed by a doctor. An 8-12 week course if your 25(OH)D test result is below 30 ng/ml. The olive oil base provides predictable absorption.
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California Gold Nutrition
Vitamin D3, 5000 IU, 90 capsules
$6.07
A practical option if you've had a test, found a shortage and want to do an intensive course without big bottles. Hypoallergenic fish gelatin shell.
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Doctor's Best
Vitamin D3, 5000 IU, 180 capsules
$9.99
A stable cholecalciferol formula for storage. Helps raise your vitamin levels before cold season and supports immunity, muscle tone and mood when you feel tired.
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NOW Foods
Vitamin D3, 10,000 IU, 120 capsules
$9.54
Maximum concentration for rapid loading protocols in cases of severe deficiency or impaired absorption. Take strictly under the control of test results or on an intermittent schedule.
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Carlson
Vitamin D3, 10,000 IU, 120 capsules
$16.92
A therapeutic dosage from a Norwegian brand. Every batch is tested by an independent laboratory for heavy metals and dose accuracy. Use in short courses to recover from a deep deficiency.
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MRM Nutrition
Vegan vitamin D3, 5000 IU, 60 veg. capsules
$19.99
Plant-based cholecalciferol D3 from lichen, not from sheep's lanolin. A great find for vegans who can't use animal-derived D3 but need to raise their levels quickly after winter.
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NOW Foods
High-potency vitamin D3, 5000 IU, 120 capsules
$5.45
A therapeutic concentration for course use as prescribed by a doctor when a deficiency is confirmed. Olive oil base for stable absorption.
Help with your purchase →
BioSchwartz
Vitamin D3, 5000 IU, 360 capsules
$14.97
A large supply of 360 high-dose capsules. Suitable for a long course to restore vitamin D levels under the control of test results.
Help with your purchase →D3 + K2 complexes (blood vessels and bones)
A combination of vitamin D3 with K2: K2 helps direct absorbed calcium into the bones rather than the walls of blood vessels. An option if you care about both bone and heart health.
Sports Research
D3 + K2 with MCT coconut oil, 5000 IU, 60 pcs
$25.97
A premium vegan complex. K2 in the MenaQ7 form directs absorbed calcium to the bones and enamel, keeping it from settling in the arteries and kidneys. Organic coconut oil ensures fast absorption.
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NOW Foods
Vitamin D3 and K2, 1000 IU / 45 mcg, 120 veg. capsules
$9.17
A gentle daily combo for regular use. Suitable for older adults and anyone who cares about joints, bone density and blood vessel elasticity. No excessive doses.
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Thorne
Liquid Vitamin D + K2, 30 ml
$34.00
A product from the medical brand Thorne, used by preventive medicine doctors. No soy lecithin, gluten, dyes or preservatives. The liquid form lets you tailor the dose for anyone in the family.
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Life Extension
Vitamins D and K with sea iodine, 60 capsules
$18.00
A three-in-one formula. A high dose of D3 is combined with all the key forms of vitamin K (K1, K2 MK-4 and MK-7) for bones and blood vessels, plus organic iodine from seaweed.
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MaryRuth's
Liquid D3 + K2 spray, vegan, 30 ml
$29.95
A tasteless vegan spray to take under the tongue or in the cheek. The vitamins are absorbed through the oral mucosa straight into the bloodstream, bypassing the stomach. Suitable for irritable bowel or bile flow problems.
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Doctor's Best
Vitamin D3 + K2 with MenaQ7, 60 veg. capsules
$15.44
A balanced dose for a safe daily base (2000 IU) with maximum blood vessel protection. The MenaQ7 form is made by soy-free fermentation and stays in the blood for a long time.
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California Gold Nutrition
Vitamins D3 and K2 (MK-7), 60 vegetarian capsules
$9.22
A D3 and K2 combo in the MK-7 form from a marketplace brand. K2 helps direct calcium into bones and enamel rather than blood vessels. Vegan capsules.
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Dr. Murray's
Vitamins D3 and K2, 60 capsules
$13.64
A vegan D3 and K2 complex for bones and blood vessels. A simple formula with no unnecessary additives, one capsule a day.
Help with your purchase →For infants and children under one year (drops, ages 0-3)
Drops for infants and children in their first year. The liquid form is easy to dose by age, and the gentle formulas without unnecessary additives suit delicate digestion.
California Gold Nutrition
Baby Vitamin D3 drops, 400 IU, 10 ml
$8.92
A choice for babies from the very first days. Contains no alcohol, sugar, preservatives, gluten or flavorings - only coconut MCT oil and cholecalciferol. The drops have a neutral taste and don't irritate the digestive tract.
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Carlson
Baby D3 Super Daily drops, 400 IU, 10.3 ml
$12.65
A well-known GMP-standard brand. The patented dispenser releases exactly one drop when turned upside down, with no stream - an overdose is impossible. No unpleasant aftertaste.
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GreenPeach
Vitamin D3 for infants, children and adults, 400 IU, 10 ml
$17.33
Liquid vitamin D3 for infants, children and adults in one bottle - 400 IU per oil-based drop. The dose is easy to adjust by age. No artificial colors or flavorings.
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Ddrops
Organic liquid D3 drops for babies, 400 IU
$17.03
A Canadian bestseller with a minimal hypoallergenic formula: fractionated coconut oil and vitamin D3, with no preservatives, soy or gluten. A drop comes out within a couple of seconds after you turn the bottle over.
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Mommy's Bliss
Organic baby Vitamin D drops, 400 IU
$12.49
A brand of products for the delicate digestion of newborns. The drops are USDA Organic certified, free of soy, dairy and alcohol. The bottle is leak-proof.
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Nature's Truth
Baby Vitamin D3 drops for newborns, 400 IU
$8.03
Baby Vitamin D3 drops for newborns - 400 IU per oil-based serving. A simple formula with no unnecessary additives and a convenient dropper. An affordable base for an infant's daily requirement.
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Absolute Nutrition
Vitamin D3 drops, 60 ml
$13.39
Simple oil-based liquid Vitamin D3 drops. Neutral taste, a convenient dropper for an accurate dose for your little one, no unnecessary additives.
Help with your purchase →
Nature's Craft
Organic D3 and K2 drops for kids, 60 ml
$18.53
Organic drops with vitamins D3 and K2 for children. K2 helps direct calcium into bones, and the dose is easy to adjust by age.
Help with your purchase →For preschoolers, school-age kids and teens
Forms for preschoolers, school-age kids and teens: tasty lozenges and drops that are easier to take than capsules. Doses are designed for a growing body.
ChildLife Essentials
Vitamin D3, wild berry flavor, 500 IU, 30 ml
$9.99
The leader among flavored children's drops from 6 months. A pleasant wild berry taste, sweetened with vegetable glycerin and no refined sugar. With the dropper, it's easy to increase the dose as your child grows.
Help with your purchase →
California Gold Nutrition
Vitamin D3 lozenges, 1000 IU, 90 pieces
$9.61
An option for children from 4 years old and teens who don't like drops or capsules. Lozenges made with citrus pectin, no gelatin. The jar contains three flavors: strawberry, lemon, orange.
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Nordic Naturals
Sugar-free children's D3 lozenges, 1000 IU, 60 pieces
$14.24
The main advantage is zero sugar. The sweetness comes from natural xylitol, which doesn't feed cavity-causing bacteria. Wild berry flavor, for children from 4 years old.
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GummiKing
Vitamin D for kids, 60 lozenges
$8.02
An affordable children's brand. The lozenges are soft, don't stick to teeth and are easy to chew. The 300 IU dose is convenient because a preschooler can take 1-2 pieces a day.
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Carlson
Baby D3 Super Daily drops, 1000 IU, 10.3 ml
$14.45
A higher children's concentration for ages 4 and up and teens in a growth phase. Just one unnoticeable drop in juice, fruit drink or porridge is enough. The taste of the oils isn't noticeable.
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SmartyPants
Kids' multivitamin + omega gummies, 60 count
$24.99
A complete solution for schoolchildren during the busy school season. Along with vitamin D3, the formula includes omega-3 (EPA and DHA), B vitamins, iodine and zinc. Covers basic deficiencies without a handful of pills.
Help with your purchase →
Garden of Life
Kids, vitamin D3, orange, 800 IU, 60 lozenges
$11.89
Kids' vegetarian gummies with vitamin D3 and orange flavor. The 800 IU dose is suitable for preschoolers and schoolchildren.
Help with your purchase →
Nordic Naturals
Kids' D3 lozenges, watermelon, 400 IU, 60 pieces
$10.58
Vitamin D3 gummies with watermelon flavor for kids ages 3 and up. The brand is known for strict quality control and clean ingredients.
Help with your purchase →Dosing schedules and amounts are for informational purposes only. If you suspect a deficiency, get a blood test and consult a doctor before you start taking it.
Vitamin D3 from the USA delivered by Prostobox
Original bottles from iHerb - with a US address, free buyout with promo code GETIHERB and home delivery in 5-10 days.
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Original
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D3
Why Prostobox is a great deal
Originals from iHerb, prices lower than at pharmacies, and cheap delivery from the US low-cost carrier.
01100% original from iHerb
You buy directly on iHerb - only genuine supplements with transparent ingredient lists and expiration dates.
02Prices lower than at pharmacies
In Russian pharmacies, the same vitamins cost noticeably more. With iHerb, you get the real price plus seasonal sales.
03Low delivery prices
The low-cost way to ship from the USA: a special iHerb rate of $9.99 per 1 kg and $29.90 per 3 kg. You pay for actual weight.
04Fast processing
Parcels are scanned and entered into the system within seconds. The AI assistant will fill out your customs declaration for free from a screenshot of your order.
05Fast support
Our support team works hand in hand with AI: the agent instantly pulls data from the database, warehouse and email. We resolve issues many times faster.
06Free buyout
No US card? Send our operators the links and we'll buy the items for you. With promo code GETIHERB, the buyout service is free.
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Service news, discounts on vitamins and sales from foreign stores - in the Prostobox channels.
FAQ
Are the vitamins from iHerb original?
Yes, only originals. Orders are placed on the official iHerb site, not through resellers. You get genuine supplements with transparent ingredients, batch labeling and an expiration date. You can also buy vitamins on the site yourself if you have a bank card that the US iHerb accepts.
Which vitamin D3 should I choose?
For infants - oil drops with 400 IU; for older kids - drops or gummies; for adults as prevention - 2000 IU capsules; for a deficiency confirmed by a test - a course of 5000-10,000 IU. For doses of 5000 IU and above, choose a D3 + K2 combo.
How do I order through Prostobox?
Sign up at prostobox.com and get your personal warehouse address in Delaware. Enter your personal address as the delivery address on iHerb, or send the links to our operators for buyout - you can send a single link for the whole cart! We'll receive the parcel at the warehouse in your locker and forward it to you.
What is free buyout with GETIHERB?
No US card? An operator will place and pay for your iHerb order for you. With promo code GETIHERB, the buyout service is free: you only pay for the supplements themselves and delivery. Pay in rubles, dollars or cryptocurrency.
How long does delivery take?
5-10 days by air from the US warehouse. Special iHerb rate: $9.99 per parcel up to 1 kg and $29.90 up to 3 kg. Weight is calculated without the box, so leave some margin for packaging.
How is vitamin D3 different from D2?
D3 (cholecalciferol) is the natural form, identical to what your skin produces in the sun, and it is absorbed faster and more reliably. D2 (ergocalciferol) is made from yeast and fungi; the body absorbs it less well, and this form is considered outdated. Choose D3.
When is it better to take vitamin D - morning or evening?
In the morning or at lunchtime. Vitamin D slightly stimulates the nervous system and suppresses production of the sleep hormone melatonin, so taking it at night may lead to insomnia.
Should I take vitamin D with food?
Yes, vitamin D is fat-soluble. Take it with a meal that contains fats - fried eggs, a sandwich with butter or cheese, avocado, porridge with milk, a handful of nuts. On an empty stomach, it's barely absorbed.
Do I need to get tested before taking it?
For prevention, 2000 IU a day is safe for an adult without any tests. If you suspect a deficiency, get a 25-OH vitamin D blood test: if the level is below 20-30 ng/ml, a doctor may prescribe a course of 5000-10,000 IU for 1-2 months.
Why is K2 added to vitamin D?
Vitamin K2 directs absorbed calcium into your bones and tooth enamel rather than the walls of your blood vessels. At doses up to 2000 IU, plain D3 is enough, while for higher doses it's better to take a D3 + K2 combination.
Can babies take vitamin D?
Yes, and it's necessary: breast milk contains very little vitamin D. For babies, choose 400 IU oil-based drops without alcohol, sugar or preservatives. The dose is easy to measure with a dropper.
Which form of vitamin D should I choose?
Oil-based drops for infants, drops or chewable lozenges for older children, capsules for adults, and liquid drops for those who find capsules hard to swallow. Each age has its own convenient form.
Is it true that most people in central Russia need vitamin D?
Yes. In Moscow, the Volga region, the Urals, Siberia and the Northwest, the sun sits too low above the horizon for most of the year. From October to May, vitamin synthesis in the skin is close to zero, so almost everyone needs a supplement.
Can I stock up on vitamin D over the summer?
No. Your body uses up its reserves in about 3-4 weeks, and what you build up on vacation won't last even until November. That's why vitamin D is taken either year-round or at least from September to May.
How do I pay for my order and delivery?
You can pay in rubles, dollars or cryptocurrency. With the promo code GETIHERB, the buyout is free: you only pay for the supplements themselves and for the parcel weight at the shipping rate.
What is iHerb?
iHerb is a large American store for vitamins, supplements and health products. It offers original products with transparent ingredient lists and expiration dates, seasonal sales and promo codes. Prostobox delivers iHerb orders to your home.
Do I need a US card to order from iHerb?
Not necessarily. If you don't have a US card, a Prostobox operator will place and pay for the order for you, and with the promo code GETIHERB this service is free. If you do have a card, you can pay yourself.
Why do I need a personal US warehouse address?
Your orders from iHerb and other stores arrive at this address in Delaware. Prostobox receives the parcel, processes it and sends it to you.
Where is the Prostobox warehouse located?
The warehouse is in Delaware, a US state with no sales tax (0%), so you save 6% to 10% in state tax on your order.
Can I combine several orders into one parcel?
Yes. The warehouse combines purchases from different orders into one consolidated box and removes extra packaging, so you save on international weight. But since there is a special shipping promotion for iHerb, it's best to send parcels of up to 1 kg or up to 3 kg, as that's more cost-effective.
How long is a parcel stored at the warehouse for free?
Every incoming parcel is stored at the Delaware warehouse for free for up to 45 calendar days. That's enough time to wait for all your purchases and combine them into one parcel.
Is there insurance for my parcel?
Yes. Insurance costs $3 for orders under $100 and $5 for orders of $100 or more, and it covers the declared value of your purchases if the parcel is lost during international delivery.
Who fills out the customs declaration?
The Prostobox AI assistant fills out the declaration for free, based on an order screenshot or a link. You don't have to deal with codes and forms manually.
Which countries does Prostobox deliver vitamins to?
Prostobox delivers orders from the US to Russia and Belarus. Delivery is by air, from the Delaware warehouse to your door or a pickup point in 5-10 days.
Can I send one link for my entire iHerb cart?
Yes. Build your cart on the US version of iherb.com (US/USD should be shown at the top), click the "Share cart" button and send one link to your Prostobox account, and the service will sort out the items itself. Copy the link using the button, not from the address bar. With the promo code GETIHERB, the buyout is free.
