GO Healthy Ester-C Cold & Flu Relief

Choosing a vitamin C form comes down to your stomach, your budget and what else you take, and our naturopaths talk people through it every day. Here's the short version.

A good fit if

• Plain vitamin C upsets your stomach or feels sharp going down
• You find acidic foods hard going in general
• You'd rather take a capsule or tablet than stir a powder into water

Check with us first if

• You've had kidney stones or been told you make too much oxalate. Oxalate excretion rose at 1,000 mg of vitamin C a day.
• You're having chemotherapy or radiotherapy. NIH advises talking to your oncologist before taking vitamin C or other antioxidant supplements.
• You take niacin with a statin. Vitamin C with other antioxidants may blunt the rise in HDL cholesterol from that combination.
• You take iron supplements or have your iron monitored. Vitamin C increases how much non-haem iron you absorb.
• You already take calcium, or you've been told to watch it. Ester-C is a calcium salt, so it adds to your daily total.
• It's for a child. Children need 35 to 40 mg a day, far less than a typical 1,000 mg capsule.

• Ester-C. Best known for: Calcium ascorbate plus vitamin C metabolites, and the buffered form with a published stomach trial. Absorption: More vitamin C in white blood cells at 24 hours than ascorbic acid, with no plasma difference, in a 15-person trial. Typical use: Buffered tablets or capsules, usually 1,000 mg.
• Plain ascorbic acid (the comparison). Best known for: The form almost every vitamin C trial used, and the cheapest per gram. Absorption: The benchmark: fully absorbed up to a 200 mg single dose, falling from 500 mg. Typical use: Tablets or powder, split across the day.
• Calcium ascorbate. Best known for: The buffered salt Ester-C is built on, without the added metabolites. Absorption: No difference from ascorbic acid at 250 mg. Some immune measures differed at 500 mg, in one preliminary single-dose trial. Typical use: Unflavoured powder stirred into water or juice.
• Liposomal vitamin C. Best known for: Vitamin C wrapped in phospholipid bubbles, at a premium price. Absorption: About 27% higher peak plasma than standard vitamin C in one blinded 500 mg trial. Typical use: Liquids, softgels and capsules.
• Sodium ascorbate. Best known for: Buffered vitamin C carrying sodium instead of calcium. Absorption: No trial we hold compares it with ascorbic acid. Typical use: High-dose powders for people who don't want the acid.

Reference values. Ester-C doesn't change how much vitamin C you need. The NHMRC RDI for adult men and women is 45 mg a day. It rises to 60 mg in pregnancy and 85 mg while breastfeeding, for ages 19 to 50. Children need 35 to 40 mg.

Typical supplemental range. The Ester-C trials we hold all used 1,000 mg of vitamin C, which matches how it's usually sold in Australia. Check your label for how much vitamin C each capsule or tablet actually gives you, because the pack often lists the whole ingredient.

Upper level. Australia hasn't set an Upper Level. The NHMRC's position, verbatim: 'It is not possible to establish a UL for vitamin C, but 1,000 mg/day is a prudent limit.' A 1,000 mg Ester-C dose already sits at that line, so count any vitamin C in your multi or other products too.

Worth knowing. A 200 mg single dose of vitamin C is fully absorbed, and absorption drops from 500 mg upward, with the extra excreted. Your needs depend on your age, diet and health circumstances. Talk to one of our naturopaths.

Food first, where the diet allows it.

• Red capsicum, raw, half a cup: 95 mg
• Orange, 1 medium: 70 mg, which already clears the adult RDI of 45 mg
• Kiwifruit, 1 medium: 64 mg
• Strawberries, sliced, half a cup: 49 mg

This list is the part of the page we will not shorten. If any of it applies to you, talk to one of our naturopaths or your doctor before starting.

• Hereditary haemochromatosis or iron overload. NIH lists iron overload among the concerns from excess vitamin C intake.
• Kidney stones or hyperoxaluria. Oxalate and urate excretion rose at 1,000 mg of vitamin C a day.
• Chemotherapy or radiotherapy. NIH advises consulting your oncologist before taking antioxidant supplements.
• Niacin with simvastatin. Vitamin C with other antioxidants may attenuate the HDL increase.
• Iron supplements or iron monitoring. Vitamin C increases non-haem iron absorption.
• Calcium supplements or calcium restriction. Ester-C is a calcium salt and adds calcium to the daily total.
• High doses generally. NIH notes diarrhoea, nausea, abdominal cramps and other stomach upsets.
• Children. The RDI is 35 to 40 mg a day.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before starting.