Low testosterone, or Low T, is something any man can suffer at any age. It is important to know the red flags of Low T so that you can get the treatment you need. However, just because a person exhibits one, or some, of these symptoms doesn’t mean testosterone is the issue. You have to have a Low T test performed by a physician for a correct diagnosis.

Here are nine signs of low testosterone to watch for, and consider going to a doctor if you experience these.

1. Lower Sex Drive: Perhaps the most well-known of all symptoms, sometimes a fledgling sex drive is actually just a sign of Low T and nothing more. Testosterone is the gasoline of sex drive for men. However, there’s no such thing as a “normal” sex drive across the board for all men— there’s just normal for one, and this will vary greatly throughout one’s life. Other factors such as age, stress levels, and perhaps another health issue can also cause low sex drive.

2. Trouble with Orgasm and Erectile Dysfunction: Difficulty in reaching orgasm may also be a sign of low testosterone. You need testosterone to achieve orgasm. Erectile dysfunction, or ED, may also be a sign of Low T. If you experience either, or both, or these symptoms, it’s time to make an appointment and see if testosterone levels are to blame.

3. Numb Genitals: This usually doesn’t mean the groin area is completely numb, but many men report that something just feels “off” in the region. If things haven’t felt quite right in this regard, it might be low testosterone.

4. Being Tired: Everyone gets tired once in awhile, especially with hectic schedules and keeping your plate too full. However, if the fatigue seems chronic or severe, low testosterone might be the culprit. Fatigue can be caused from all sorts of things, but don’t discount the possibility that serious fatigue may be your only red flag.

5. Lack of Ambition: Similar to fatigue, some men simply lose their drive to do, well, much of anything besides sit on the couch. If you’ve been a couch potato recently and that’s not you, it’s time to check for Low T.

6. Feeling Blue: If you feel depressed, down in the dumps, or just can’t quite muster up the ambitions and optimism you used to have, that might be a symptom of low testosterone. Everyone gets down now and then, and this doesn’t necessarily mean anything (including Low T) is to blame, but it’s worth considering.

7. Losing Muscle: If you haven’t hit the weights in a few weeks, that’s probably the culprit. However, if you’ve kept up with your usual exercise routine, or even if you don’t work out regularly and have noticed muscle shrinkage, it might be caused by low testosterone. However, for gym rats, don’t discount the idea that your muscles quickly get used to lifting schedules and you might just need to mix things up.

8. More Fat: If you’ve been swapping muscle for fat but haven’t changed your diet or exercise regimen, you might be suffering from low testosterone. It’s natural to put on a little more padding as you age, but if it’s seemingly overnight, there’s probably an issue to address.

9. Shrinking Testicles: It’s true. Low testosterone can cause testicles to shrink in size, but don’t worry—it’s not permanent. Size actually does matter, at least when it comes to testosterone levels.

What About Testosterone Gels?

Testosterone gel and testosterone cream products seem like an easy solution for treating low testosterone levels, and a number of men have been flocking to these products. While some men see minor improvements when it comes to building muscle and losing fat, when it comes to endurance and generally feeling better, new research says that testosterone gel products don’t work.

The University of Colorado’s School of Medicine Dr. Kerry Hildreth oversaw a study that revealed testosterone gel “is widely used in people where it really may not be appropriate or may not provide the benefits that people think it’s going to.”

However, there’s more to this phenomenon of men stockpiling testosterone gel than wasted money. It can actually be dangerous.

The long-term side effects of testosterone can include a 30 percent increase in the risk of heart attack, stroke or death.

“People should be careful using it,” says Dr. Hildreth.

Both elevated prostate-specific antigen levels and abnormal blood counts were found in men who used the gels. In a study of 8,700 men published in the Journal of the American Medical Association, in just three years thousands of men faced a huge spike in these deadly testosterone gel complications.

Men lose testosterone as they age—to some degree, it’s normal. However, a number of low testosterone products are showing that they provide zero or very little benefits, but come with a smorgasbord of dangerous complications.