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Which supplements help with sleep and stress
The short answer. What holds up with sources is short: melatonin, about €0.72 a month at the dose used in the studies. This page lists 3 supplements with evidence for this goal, and 1 sold for it that you do not need.
Bad sleep is not fixed with a tub, but two of these have a measured, cheap effect. The rest of what is sold on this shelf is a multivitamin with a night-time name.
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The basics, and what they cost
Melatonin
€0.72a month
1 mg. Going up to 3, 5 or 10 mg does not improve the effect and increases grogginess the next day.
Cheapest at that dose: Melatonina 1,95 mg PURA - 500 Comprimidos from Amazon, €0.024/capsule.
€0.72 a month in total, adding up melatonin at one effective dose a day with the cheapest product that reaches that dose. It is not a medical recommendation or a plan: it is what the evidence-backed options cost today, in the stores this site compares.
The 3 with something behind them
By evidence level and monthly cost
| Supplement | Evidence | What has been measured | Per month |
|---|---|---|---|
| Melatonin1 mg. Going up to 3, 5 or 10 mg does not improve the effect and increases grogginess the next day. | Strong evidence116 products compared · best score: Melatonina 365 Tabletas (1 Año de suministro) - Complemento de melatonina pura para jet lag e insomnio - Alta dosis para calidad de sueño - Probado en laboratorio from Amazon | Time to fall asleep: a few minutes lessReglamento (UE) 432/2012 de la Comision: lista de declaraciones autorizadas. La melatonina contribuye a disminuir el tiempo necesario para conciliar el sueno; condicion de uso: 1 mg por porcion, poco antes de acostarse. | €0.72 |
| MagnesiumWhatever is missing to get close to the day’s 375 mg counting food, not the whole tub by default. | Moderate evidence154 products compared · best score: Santiveri Santiveres Cloruro de Magnesio 200 caps from PromoFarma | Functions authorised in the EU: muscle, nervous system and tirednessReglamento (UE) 1169/2011 sobre la informacion alimentaria facilitada al consumidor, Anexo XIII: valores de referencia de nutrientes. Magnesio, 375 mg. | €1.61 |
| Ashwagandha300 to 600 mg a day of standardised extract, split or in one serving. | Moderate evidence119 products compared · best score: Ashwagandha en Comprimidos 2000 mg | 6 Meses de Suminstro - 365 Comprimidos Veganos | Withania Somnifera | Alta Potencia | Formato Ahorro | Horbaach from Amazon | Perceived stress: improves versus placeboPratte MA et al. An alternative treatment for anxiety: a systematic review of human trial results reported for the Ayurvedic herb ashwagandha (Withania somnifera). J Altern Complement Med. 2014;20(12):901-908. | €7.24 |
The 1 they will try to sell you for this
Weak evidence, supplement price
Reviews find no consistent effect. It is listed because it sells, not because it works.
| Supplement | What has been measured | Per month |
|---|---|---|
| ZMAZMA is not an ingredient: it is a specific formula of zinc, magnesium and vitamin B6 that became popular as a hormone booster. | Testosterone in trained athletes: no changeWilborn CD et al. Effects of Zinc Magnesium Aspartate (ZMA) supplementation on training adaptations and markers of anabolism and catabolism. J Int Soc Sports Nutr. 2004;1(2):12-20. Sin cambios en testosterona ni en las adaptaciones al entrenamiento frente a placebo. | no published dose |
Weak evidence is not fraud. It means the effect does not show up when diet already fills the gap, or that the studies behind it are small, short or paid for by the seller. Each guide says in which specific case it does make sense, which almost always exists and is almost never the case of the person buying it.
Questions about supplements for: sleep and stress
Answered with the data on this page
- Which supplements should you take to sleep and stress?
- The minimum you can defend with sources is melatonin, which at the dose used in the studies comes to €0.72 a month buying the cheapest that reaches that dose. Beyond that, this page lists another 2 with evidence behind them, each for a specific case.
- And zma?
- ZMA has weak evidence for this: Reviews find no consistent effect. It is listed because it sells, not because it works. They are sold a lot for this goal and each has its own guide with the sources, so the decision does not depend on what a label says.
- Where do these prices come from?
- From the 4065 products this site collects across 19 Spanish stores, with prices from October 15, 2026. The monthly cost is one effective dose a day for 30 days, with the cheapest product that reaches that dose. The evidence was reviewed on September 4, 2026.
Other goals
The same list, another question