Supplements for stress, such as ashwagandha, L-theanine and magnesium, have some early research behind them, but the studies are small and none of them replaces proper support. They may help you feel a little more settled during a busy patch, yet if stress or worry is affecting your sleep, work or relationships, the best first step is a chat with your GP.
This guide covers what each one is, what the research really shows, the safety points to know, and how to choose in Australia.
Ashwagandha, L-theanine and magnesium at a glance
| Ashwagandha | L-theanine | Magnesium | |
|---|---|---|---|
| What it is | Root extract of the herb Withania somnifera | Amino acid found in tea | Essential mineral |
| Amounts used in studies | 300 to 600 mg of extract a day for stress | 200 to 400 mg a day | Varied widely |
| Strength of evidence | 12 small trials, low certainty | A handful of small trials | Suggestive, but poor quality |
| Main caution | Very rare liver injury (TGA), ask your doctor if pregnant | Check labels so you do not double up | High doses can loosen stools |
| Example at Supps247 | ALLMAX Ashwagandha KSM-66 (30 serves), $59.95 | Best Naturals L-Theanine 200 mg (120 tablets), $49.95 | Beast Labs Magnesium Bi-Glycinate (60 caps), $29.95 |
Prices are at the time of writing.
When to see your GP first
Stress is a normal reaction to pressure, and short bursts of it are part of life. But healthdirect describes stress as a clue that something else may be going on, and says ongoing stress can be a sign of anxiety, depression or another mental health condition. Anxiety is a health condition, and no supplement is designed to manage it.
Talk to your GP if you have felt overwhelmed for more than a couple of weeks, your sleep has changed, you feel exhausted, you are leaning on alcohol to cope, or things you used to enjoy feel flat. GPs and psychologists are trained to spot when stress needs extra support, and they can check whether a supplement is safe with any medicines you take. Beyond Blue offers free information and counselling. If you are in crisis, call Lifeline on 13 11 14, or 000 in an emergency.
Ashwagandha: the most studied, with a safety note
Ashwagandha has the most research of the three. A 2022 meta-analysis by Akhgarjand and colleagues pooled 12 trials with 1,002 adults and found lower scores on stress and anxiety questionnaires with ashwagandha than with placebo. The trials ran for 8 to 12 weeks, and the stress benefit was seen at 300 to 600 mg a day. The authors rated the certainty of the evidence as low, because results varied a lot between trials and the samples were small, and they called for more high-quality studies.
There is also a safety point. The TGA has warned that products containing ashwagandha may be linked to liver injury in very rare cases. Most Australian cases settled after the product was stopped. The TGA says to avoid it if you have or have had liver problems, and to stop and see a doctor if you notice yellowing of the skin or eyes, dark urine, nausea, unusual tiredness or stomach pain. Some experts advise against ashwagandha during pregnancy, so speak with your doctor first if you are pregnant or breastfeeding, or if you take prescription medicines.
If you want to try it, two options at Supps247 match the studied range:
- ALLMAX Essentials Ashwagandha KSM-66 gives 600 mg of KSM-66 root extract per two capsule serve (300 mg a capsule), so you can take one or two a day. The 30 serve bottle works out at about $2.00 per full serve.
- Beast Labs Ashwagandha 600mg gives 600 mg of extract standardised to 5% withanolides in one capsule, at about $1.00 a day. It is one of our best selling ashwagandha products over the last six months.
Give it the 8 weeks the trials used before you judge it. Read more in our ashwagandha benefits explainer or compare brands in our best ashwagandha guide.
L-theanine: a gentle option from tea
L-theanine is an amino acid found naturally in green and black tea. A 2020 systematic review by Williams and colleagues looked at nine studies and found that 200 to 400 mg a day was linked with lower stress and anxiety scores in people under stressful conditions. The studies were small and short, so see this as early research rather than proof.
Best Naturals L-Theanine 200mg is a simple single-ingredient tablet with 200 mg per tablet and 120 tablets a bottle, about $0.42 each. L-theanine is also added to many pre-workouts and focus products, so check your other labels and count the total.
Magnesium: most useful if your intake is low
Magnesium is needed for normal nerve and muscle function. A 2017 systematic review by Boyle and colleagues looked at 18 studies and found only suggestive, poor-quality evidence of lower anxiety scores in people prone to anxiety. In plain terms, magnesium is worth getting right, but do not expect it to change how stressed you feel overnight.
Food comes first: nuts, seeds, wholegrains, legumes and leafy greens are good sources. If your diet falls short, Beast Labs Magnesium Bi-Glycinate 750mg gives 150 mg of elemental magnesium per capsule, with 60 capsules for $29.95, about $0.50 a day. Large doses of any magnesium supplement can cause loose stools, so stick to the label dose. If you have kidney problems, check with your GP before taking magnesium. For help choosing a form, see our best magnesium supplement guide.
Habits that matter more than any capsule
- Move every day. healthdirect notes daily exercise has many benefits for your wellbeing, including reducing stress.
- Protect your sleep. Keep regular sleep and wake times, and watch how much caffeine you have from coffee and pre-workout later in the day.
- Talk to someone. A friend, family member, your GP or a counsellor. It is the step healthdirect suggests before anything else.
Which supplement for stress should you choose?
If you want the option with the most research, choose ashwagandha, ideally a studied extract like ALLMAX KSM-66, as long as you have no liver problems, and after checking with your doctor if you are pregnant or on medication. For something gentle on busy days, L-theanine is a reasonable, low-cost trial. If your diet is low in magnesium or you train hard, magnesium glycinate covers a basic need. Start with one product at a time so you can tell what is helping, and stop if you notice side effects.
Our pick for most people is ALLMAX KSM-66 for an 8 week trial, alongside better sleep and daily exercise. And if stress is sticking around, see your GP. Browse our ashwagandha range or our magnesium range. Online orders ship Australia-wide with free shipping on orders of $99.99 or more, and click and collect and Afterpay are available.
Shop the products in this guide
ALLMAX Ashwagandha KSM-66$59.95
Beast Labs Ashwagandha 600mg$59.95
Best Naturals L-Theanine 200mg$49.95
Beast Labs Magnesium Bi-Glycinate$29.95
Browse all ashwagandha and magnesium supplements.
FAQs
What is the best supplement for stress?
Ashwagandha has the most research, with a 2022 meta-analysis of 12 small trials finding lower stress scores at 300 to 600 mg a day, though the certainty of evidence was low. L-theanine and magnesium have smaller and weaker evidence. None of them replaces sleep, exercise and support from people around you. If stress has lasted weeks or is affecting daily life, see your GP first.
How long does ashwagandha take to work?
The trials in the 2022 meta-analysis ran for 8 to 12 weeks, so give it at least 8 weeks at a studied dose of 300 to 600 mg of extract a day before you judge it. Some people notice nothing, and that is normal given the mixed results. Stop taking it and see a doctor if you notice yellowing of the skin or eyes, dark urine, nausea or unusual tiredness.
Is ashwagandha safe?
Ashwagandha is widely used, but the TGA has warned that ashwagandha may be linked to liver injury in very rare cases. Avoid it if you have or have had liver problems, and speak with your doctor first if you are pregnant, breastfeeding or take prescription medicines, and stick to the label dose. Report any suspected side effect to your doctor or the TGA.
Can supplements help with anxiety?
Anxiety is a health condition, and supplements are not designed to manage it. Some small studies of ashwagandha, L-theanine and magnesium reported lower scores on anxiety questionnaires, but the evidence is limited. If you are dealing with ongoing worry, panic or low mood, talk to your GP, who can discuss options that have strong evidence. Beyond Blue also has free information and counselling.
Can I take L-theanine with my pre-workout?
Many pre-workouts and focus products already contain L-theanine, so check the label before adding a separate tablet. Studies on stress used 200 to 400 mg a day in total. L-theanine itself contains no caffeine, but if you take pre-workout late in the day, the caffeine may affect your sleep, which matters far more for stress than any added ingredient.
Sources: healthdirect: stress; Beyond Blue; TGA safety alert: herbal preparations containing Withania somnifera (ashwagandha), July 2026; Akhgarjand et al. Ashwagandha for anxiety and stress, meta-analysis (2022); Williams et al. L-theanine and stress, systematic review (2020); Boyle et al. Magnesium, anxiety and stress, systematic review (2017); product labels and brand nutrition panels, checked October 2026.
Order online with Australia-wide delivery, free on orders of $99.99 or more, with Afterpay available at checkout. You can also use click and collect at a store that offers it, or visit a Supps247 store in Melbourne, regional Victoria or Brisbane to compare products in person. Members can use our member price match on full-priced items.
Prices and stock were checked on 29 October 2026 and can change at any time. Always read the label and follow the directions for use. If you have a medical condition, are pregnant or take regular medication, check with your doctor first.
