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L-Tryptophan

Also called tryptophan.

The best price per 500 mg and per month, form by form, across 2 UK retailers, and where to buy it cheapest. A unit for comparing, not advice.

Comparing L-Tryptophan

We count the L-tryptophan a label states per serving, whatever the pack size or the serving size, so every product sits on one scale. Products that combine L-Tryptophan with other ingredients are listed separately, because their price buys more than L-tryptophan. 500 mg is our unit for comparing prices, not a dose to take: the label’s directions and a pharmacist decide that.

L-Tryptophan

Prices last checked: . Ranked purely by price per 500 mg — a comparison unit, not a recommendation. We earn commission when you buy through these links; it never affects the order.

Compared at 500 mg. Enter the amount you take to see your own costs.

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L-Tryptophan, L-Tryptophan: products ranked by price per 500 mg
RankProductPer 500 mgPer monthLastsBuyHow it is worked out
1
Bulk Tryptophan
Cheapest per doseTryptophan100 g · 454.5 servings · 220 mg a servingDetails and price historyAdd to my stack
2p75p7 months£4.99View at Bulk (opens in a new tab)Free delivery over £49.00, otherwise £3.95AmazonFind it on Amazon (opens in a new tab)A search, not a matched product. Price not compared.
Show the working
  • Servings: 100 ÷ 0.22 per serving = 454.5
  • In the pack: 454.5 × 220 mg = 100 g
  • £4.99 ÷ 100 g × 500 mg = 2.5p per 500 mg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “100g”
  • units per serving “Per Serving (220 mg)”
  • amount per serving “[L-Tryptophan ; 220mg]”

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2
NOW Foods L-Tryptophan 500mg - 60 vcaps
Best value under 6 months' supplyL-Tryptophan 500mg - 60 vcapsHealf · 60 capsules · 30 servings · 1 g a servingDetails and price historyAdd to my stack
22p£6.502 months£12.99View at Healf (opens in a new tab)Free delivery over £50.00, otherwise £3.99AmazonFind it on Amazon (opens in a new tab)A search, not a matched product. Price not compared.
Show the working
  • Servings: 60 ÷ 2 per serving = 30
  • In the pack: 30 × 1 g = 30 g
  • £12.99 ÷ 30 g × 500 mg = 21.6p per 500 mg
  • Amount per serving: stated on the label.
What the retailer's listing says
  • pack units “60 vcaps”
  • servings stated “Servings Per Container: 30”
  • units per serving “Serving Size: 2 Veg Capsules”
  • amount per serving “L-Tryptophan (Free-Form) (1 g) ; 1000 mg”

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How we work out these prices

We count the amount of L-tryptophan per serving as stated on the label.

Questions

Where can I buy L-Tryptophan cheapest in the UK?

On 20 October 2026, the cheapest L-Tryptophan per dose from a UK seller was Tryptophan at Bulk (2p per 500 mg, 75p a month). Then L-Tryptophan 500mg - 60 vcaps at Healf (22p per 500 mg, £6.50 a month). That is by price per 500 mg, across 2 UK retailers and 2 products, with every price checked daily; the table above shows the working for each.

What is the best price per 500 mg of L-Tryptophan today?

2p per 500 mg, for Tryptophan at Bulk (2p per 500 mg, 75p a month), on 20 October 2026. The dearest of the 2 products we price is 22p per 500 mg, and the middle one is 12p.

How much does L-Tryptophan cost per month?

At one 500 mg dose a day, the cheapest works out at 75p a month, for Tryptophan at Bulk, on 20 October 2026. Across the 2 products we price it runs from 75p to £6.50 a month. A month is 30 days, and the figure follows the dose you enter in the table.

How long does a pack of L-Tryptophan last?

At one 500 mg dose a day, the packs we price last from 2 months to 7 months; the middle one lasts 4 months. Each row says how long its pack lasts at the dose you enter.

What does “per 500 mg” mean?

It is the unit we use to put every product on the same scale: the price of 500 mg of L-tryptophan, whatever the pack size or serving size. It is a comparison unit, not a recommendation of how much to take. Use the “Your daily dose” box to see costs at the amount you actually take.

Why is a product I have seen in the shops missing?

If a retailer’s listing does not let us confirm the amount per serving, the pack size or the form, we do not guess and we do not show the product. It appears once its label has been read and confirmed.

How up to date are the prices?

Prices on this page were last checked on 20 October 2026. Every table shows the date its prices were checked. Always confirm the price on the retailer’s site before buying.

Do retailers pay to appear higher?

No. We earn a commission when you buy through our links, but the order is set only by price per dose. No retailer or brand can pay for position.