One thing I should mention before I start this article is that a lot of the research on testosterone is contradictory, so whilst one study will tell you that Vitamin D increases testosterone  another will say that it doesn’t . Who’s correct?
Smarter people than myself can argue over that, but in cases like this I will lean towards the research that shows a connection.
So, why are guys so interested in boosting their testosterone?
Firstly, studies have shown that higher testosterone levels will increase muscle protein synthesis, which leads to more muscle mass .
They might improve mood in people with depression , may improve libido .
Increased Testosterone can also decrease body fat .
Whilst the myth that increased testosterone increases violence or bullying behaviour has been disproven  high testosterone levels has been linked to power and social dominance . Whether this is cause or effect, I do not know.
Does testosterone cause social dominance, or are people who are socially dominant naturally producing more testosterone? Who cares! I want more.
How can you Boost your Testosterone Levels naturally?
Obviously, many people in the bodybuilding world have decided to skip nature and dive straight into the injectable form of testosterone.
Interestingly, testosterone is one of the oldest marketed drugs  and when used correctly it is one of the safest. But since the Cold-war era athletes started taking it in massive doses, testosterone has become one of the most common black market drugs in Bodybuilding.
Considering the huge dangers involved with abusing steroids, I am going to concentrate on simple, safe, and legal ways to increase testosterone.
1. Don’t be a Vegetarian
A lot of vegetarians and vegans will probably get irritated by this first point but the science shows again and again  that Vegetarians have lower testosterone levels than your typical Omnivore.
Having a diet which contains a lot of red meat seems to be very good for those of us who want higher testosterone levels.
If you are a vegetarian, there is no need to renounce your lifestyle and start buying steaks, just follow the next few steps and you should see dramatically increased testosterone.
For the meat-eaters amongst you, eating more meat is a great place to start your journey!
2. Eat more Fat
Hamalainen et al (1984) found that decreasing the amount of fat in your diet lowered the serum concentrations of testosterone, androstenedione, and free testosterone . This has been backed up by further studies  which all show that higher dietary fat intake and higher testosterone are linked.
Now obviously, if you are looking to lose weight a high-fat diet is going to be difficult to achieve (whilst staying within your calorie target) so if you are in a cutting phase it will be important to follow the following steps to keep your testosterone levels high.
For those of you trying to bulk up though, a high fat, high protein diet will help to boost your testosterone levels.
3. Perform Free-Weight Exercises
A study by Shaner et al (2014) compared the hormonal response to a free weight exercise (squats) and a machine weight exercise (leg press).
It found that the free weight exercise induced a greater hormonal response  with both testosterone and growth hormones (GH) higher afterwards.
Another study found that Kettlebell swings produced increased testosterone and GH , whilst this study by Andrada et al (2006) found that a strength program led to a 40% increase in testosterone .
4. Use Legal Supplements
Personally, I’m always a little dubious when it comes to companies promoting testosterone boosting supplements. As mentioned above, some studies seem to support them whilst others argue that they didn’t find enough evidence to support that claim.
The first one is Zinc-Magnesium which was found to increase both testosterone and GH in a study on football playes . The second supplement is the one I mentioned at the beginning of this article, Vitamin D  just because it is so easy to obtain. Just stand out in the sun a little bit more!
The final supplement if you are looking for a legal testosterone booster is Testogen.
This supplement contains various ingredients that have been shown to boost your own natural testosterone levels. It is completely safe, and also legal to buy.
How awesome is this? To boost your testosterone levels (or to prevent your testosterone levels from dropping) all you need to do is to sleep more!
A study by Goh & Tong (2010) found that sleep duration was associated with androgen concentrations in men .
Another study by Penev (2007) found a relationship between sleeping less affected morning testosterone levels . So sleep 8,9 or even 10 hours and you might find that your testosterone levels are significantly raised!
There you have it, 5 ways to increase testosterone levels safely (and legally) that you can do right now!
For many more testosterone boosting tips you should check out this article.
 Wehr, E., Pilz, S., Boehm, B., Marz, W., Obermayer-Pietsch, B. 2010. Association of Vitamin D status with serum androgen levels in men. Clinical Endocrinology 73(2):243-8
 Heijboer, A., Oosterwerff, M., Schroten, N., Eekhoff, E., Chel, V., de Boer, R., Blankenstein, M., Lips, P. 2015. Vitamin D supplementation and testosterone concentrations in male human subjects. Clinical Endocrinology 83(1): 105-10
 Griggs, R., Kingston, W., Jozefowicz, R., Herr, B., Forbes, G., Halliday, D. 1989. Effect of Testosterone on muscle mass and muscle protein synthesis. Journal of Applied Physiology 66(1): 498-503
 Barrett-Conner, E., Von Muhlen, D., Kritz-Silverstein, D. 1999. Bioavailable testosterone and depressed mood in older men: The Rancho Bernardo Story. The Journal of Clinical Endocrinology & Metabolism 84(2): 573-7
 Isidori, A., Giannetta, E., Gianfrilli, D., Greco, E., Vincenzo, B., Aversa, A., Isidori, A., Fabbri, A., Lenzi, A. 2005. Effects of Testosterone on sexual function in men: results of a meta-analysis. Clinical Endocrinology 63(4): 381-394
 Snyder, P., Peachey, H., Hannoush, P., Berlin, J., Loh, L., Lenrow, D., Holmes, J., Dlewati, A., Santanna, J., Rosen, C., Strom, B. 1999. Effect of Testosterone Treatment on Body Composition and Muscle Strength in Men Over 65 Years of Age. The Journal of Clinical Endocrinology & Metabolism 84(8): 2647-2653
 Schaal, B., Tremblay, R., Soussignan, R., Susman, E. 1996. Male Testosterone Linked to High Social Dominance but Low Physical Aggression in Early Adolescence. Journal of the American Academy of Child & Adolescent Psychiatry 35(10): 1322-1330
 Handelsman, D. 2006. Testosterone: use, misuse and abuse. The Medical Journal of Australia 185(8): 436-439
 Belanger, A., Locong, A., Noel, C., Cusan, L., Dupont, A., Prevost, J., Caron, S., Sevigny, J. 1989. Influence of diet on plasma steroid and sex plasma binding globulin levels in adult men. Journal of Steroid Biochemistry 32(6): 829-833
 Hill, P., Wynder, E. 1979. Effect of a vegetarian diet and dexamethasone on plasma prolactin, testosterone and dehydroepiandrosterone in men and women. Cancer Letters 7(5): 273-282
 Howie, B., Shultz, T. 1985. Dietary and hormonal interrelationships among vegetarian Seventh-Day Adventists and nonvegetarian men. The American Society for Clinical Nutrition 42(1): 127-134
 Raben, A., Kiens, B., Richter, E., Rasmussen, L., Svenstrup, B., Micic, S., Bennett, P. 1992. Serum sex hormones and endurance performance after a lacto-ovo vegetarian and a mixed diet. Medicine & Science in Sport & Exercise 24(11): 1290-7
 Hamalainen, E., Aldercreutz, H., Puska, P., Pietinen, P. 1984. Diet and serum sex hormones in healthy men. Journal of Steroid Biochemistry 20(1): 459-464
 Reed, M., Cheng, R., Simmonds, M., Richmond, W., James, V. 1986. Dietary Lipids: An Additional Regulator of Plasma levels of Sex Hormone binding Globulin. Journal of Clinical Endocrinology & Metabolism 64(5): 1083-1085
 Timothy J. A. Key, Liane Roe, Margaret Thorogood, John W. Moore, Graham M. G. Clark and Dennis Y. Wang (1990). Testosterone, sex hormone-binding globulin, calculated free testosterone, and oestradiol in male vegans and omnivores. British Journal of Nutrition, 64, pp 111-119. doi:10.1079/BJN19900014.
 Shaner, A., Vingren, J., Hatfield, D., Budnar, R., Duplanty, A., Hill, D. 2014. The Acute Hormonal response to free weight and machine weight resistance exercise. Journal of Strength & Conditioning Research 28(4): 1032-40
 Budnar, R., Duplanty, A., Hill, D., McFarlin, B., Vingren, J. 2014. The Acute Hormonal Response to the Kettlebell Swing Exercise. Journal of Strength & Conditioning Research 28(10): 2793-800
 Andrada, R., Marino, M., Marin, D., Camacho, O., Caballero, M., Marino, J. 2006. Variations in Urine Excretion of steroid hormones after an acute session and after a 4-week programme of strength training. European Journal of Applied Physiology 99(1): 64-71
 Brilla, L., Conte, V. 2000. Effects of a Novel Zinc-Magnesium Formulation on Hormones and Strength. Official Journal of the American Society of Exercise Physiologists 3(4): 26-36
 Goh, V. Tong, T. 2010, Sleep, sex steroid hormones, sexual activities, and ageing in Asian men. Journal of Andology 31(2): 131-7
 Penev, P. 2007. Association between sleep and morning testosterone levels in older men. Sleep 30(4): 427-32