Thermogenic-Boosting Complex

Not worth it

I’m always excited to see what new weight loss supplements have to offer. However, Dexyfen is disappointing. Its formula lacks proven ingredients. Many dosages are hidden, so I can’t see what amounts are used. Dexyfen contains a thiamin dosage that could easily cause side effects. And yohimbe–which may be dangerous–is included in an unknown dosage.

  • Ingredient Quality
  • Ingredient Amount
  • Negative Side Effects
  • Value

I know it sometimes feels like your body is fighting your weight loss efforts. In reality, the body has several ways to enhance weight loss. The newly-released Dexyfen is supposed to stimulate a process called thermogenesis.

When thermogenesis happens, calories burn faster and body heat increases. This leads to higher energy and fat loss.

My goal was to find out if Dexyfen is effective. But there were other things I wanted to know before recommending this weight loss supplement.

Who Makes Dexyfen?

February 2013 marks Image Sports’ 1 year anniversary. Although new, the company already has 1,400 followers–and counting–on Facebook.

Image Sports teamed with GNC to create the “Perfect GNC Franchise and Corporate Product Line.” They claim GNC is their only retailer, but Dexyfen is actually sold on several sites.

Image Sports makes performance-enhancing supplements, thermogenics, testosterone boosters, and muscle building kits. Dexyfen is a thermogenic in capsule-form.

User Reviews & Ratings

The best place to find Dexyfen user reviews is Currently, the site has 81 reviews. On a 1-5 scale, Dexyfen received 3.6 stars. 70% of users said they would recommend Dexyfen to others. These ratings and percentages are good, but I’ve seen better.

More often than not, users said Dexyfen worked. It suppressed appetite, increased energy, and helped them shed fat. Dexyfen worked fast, too. However, I was surprised and concerned by how many users reported side effects.

Several people said Dexyfen causes:

• Itchy, burning, red skin
• Burning in the throat
• Flushing
• Sweating
• Mild to severe hives
• Racing heartbeat

Several users thought they were experiencing an allergic reaction and took Benadryl. One user seemed to believe niacin was to blame. Dexyfen does contain 30 mg niacin. However, this dosage is not large enough to cause severe side effects.

Let’s see which Dexyfen ingredients produce results and which ones cause side effects.

The Dexyfen Ingredients

Dexyfen contains 7 natural ingredients. Unfortunately, natural ingredients don’t automatically make a weight loss supplement safe.

Thiamin (120 mg) is vitamin B1. It converts sugar into energy, produces acetylcholine, improves brain function, and metabolizes carbohydrates. The recommended dosage for adults is 1-2 mg. Dexyfen contains 8000% of your daily value! says overdosing on thiamin may cause allergic reactions and skin irritation.

Niacin (30 mg) comes from vitamin B3. It lowers cholesterol, unclogs arteries, and prevents diabetes. The recommended niacin dosage may cause minor burning, itching, and redness in skin. Dexyfen contains 150% of your daily value. This amount is more than you need, but not toxic.

These ingredients are combined in a proprietary blend (555 mg):

Caffeine is a powerful thermogenic. It increases energy expenditure and thermogenic response, which burns fat calories. Caffeine also enhances focus and boosts stamina. Effective dosages are between 100-400 mg.[1] These dosages may cause restlessness, insomnia, increased heart rate, and stomach upset. The more sensitive you are to caffeine, the more severe the side effects are.

Oryza sativa is the scientific name for rice. Scientists discovered it may increase thermogenesis. But these tests took place in a lab, under a microscope.[2] Oryza sativa’s thermogenic properties were not tested in humans.

Mentha haplocalyx is just mint. It freshens your breath and makes delicious tea. But mint doesn’t boost metabolism or stimulate thermogenesis on its own. At least, there are no lab, animal, or human studies proving it does.

Zanthoxylum piperitum is a Japanese pepper. Many peppers contain capsaicin, which burns fat by increasing thermogenesis. However, Zanthoxylum piperitum does not contain capsaicin. It may improve digestion, but doesn’t burn fat. On the plus side, it appears to be safe.[3]

Pausinystalia yohimbe is a stimulant and aphrodisiac. Research shows it burns fat and enhances physical performance.[4] But at what cost? says, “Yohimbe, taken by mouth, is possibly unsafe.” It has been linked to rapid heartbeat, kidney failure, nausea, and seizure. The most common dosage is 15-30 mg, which may be unsafe. Some take as much as 100 mg, which may be dangerous.

Is Dexyfen Safe and Effective?

According to reviews, Dexyfen is effective for many users. This surprises me because only caffeine and yohimbe were clinically proven to increase thermogenesis. I don’t know what dosages Dexyfen uses because the proprietary blend hides them. The other 3 main ingredients have no research proving they increase thermogenesis. This makes me wonder why Image Sports uses them.

I would also like to know why Dexyfen contains way too much thiamin! It’s likely thiamin, niacin, and yohimbe caused the side effects users experienced. Thiamin and niacin are safe in recommended dosages, which Dexyfen exceeds. But yohimbe may not be safe in any dosage.

Best Places to Buy Dexyfen

The Dexyfen bottle holds 56 capsules. Only take 1 capsule a day, in the morning, on an empty stomach. Taking 2 or more may cause serious side effects.

These are the best places to buy Dexyfen online. It’s also sold in GNC stores.

• $39.99 (Special promotion)
• $44.99
• $44.99

You won’t find a money back guarantee on these sites. But does have a limited return policy. You can return unused bottles within 30 days for a full refund.

Is Dexyfen Worth Buying?

I’m always excited to see what new weight loss supplements have to offer. However, Dexyfen is disappointing. Its formula lacks proven ingredients. Many dosages are hidden, so I can’t see what amounts are used. Dexyfen contains a thiamin dosage that could easily cause side effects. And yohimbe–which may be dangerous–is included in an unknown dosage.

Several users said Dexyfen works and is worth taking. But several users experienced side effects ranging from mild to severe.

I don’t recommend buying Dexyfen. There are many better options on the market.


[1] Astrup, A, S Toubro, et al. “Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteers.” American Journal of Clinical Nutrition. 51.5 (1990): 759-767.

[2] Zhou, PJ, HT Zhou, et al. “Studies on the energy release of rice mitochondria under different conditions by means of microcalorimetry.” Journal of Biochemical and Biophysical Methods. 48.1 (2001): 1-11.

[3] Hwang, Eun-Sun, and Gun-Hee Kim. “Safety evaluation of Zanthoxylum piperitum-derived essential oil by assessing micronucleus abnormalities, mutagenicity, and chromosomal aberration.” Food Research International. 47.2 (2012): 267-271.

[4] Ostojic, SM. “Yohimbine: the effects on body composition and exercise performance in soccer players.” Research in Sports Medicine 14 (2006): 289–99.