Of course, cardio is an important part of fitness too, but the benefits of strength training are major. Strength training helps build muscle, and lean muscle is better at burning calories when the body is at rest, which is important whether you're trying to lose weight or maintain it. It also helps strengthens joints and bones, avoid injury, improve your muscular endurance, and will help you give it your all during your other workouts, whether that means setting a new PR if you're a runner or pushing (and pulling) a little harder with your legs during your favorite indoor cycling class.
There have also been concerns that creatine can cause kidney damage, and doctors warn that people with a history of kidney disease or conditions, such as diabetes, that increase the risk of kidney problems should steer clear of the supplement. Combining creatine with nephrotoxic drugs — drugs that might damage the kidneys — like nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (advil or motrin) and naproxen sodium (Aleve), should also be avoided, according to the U.S. Department of Health and Human Services. (1)
D-aspartic acid can also help to reduce cortisol levels. Cortisol is known as the “stress” hormone because its production increases during stressful situations. High cortisol levels can have many negative side effects, such as weight gain, muscle tissue breakdown, or increased blood sugar. Taking a supplement that includes cortisol can reduce stress and prevent excess fat storage or muscle loss.
Rheumatoid arthritis. Early research shows that taking creatine by mouth daily increases lean muscle mass and may improve muscle strength, but does not improve physical functioning in adults with rheumatoid arthritis. In children, taking a specific supplement containing creatine and fatty acids twice daily for 30 days might reduce pain and swelling. But the effects of creatine alone are not clear.
Weight training has also been shown to benefit dieters as it inhibits lean body mass loss (as opposed to fat loss) when under a caloric deficit. Weight training also strengthens bones, helping to prevent bone loss and osteoporosis. By increasing muscular strength and improving balance, weight training can also reduce falls by elderly persons. Weight training is also attracting attention for the benefits it can have on the brain, and in older adults, a 2017 meta analysis found that it was effective in improving cognitive performance.[38]

Creatine ethyl ester increases muscle levels of creatine to a lesser degree than creatine monohydrate.[72] It may also result in higher serum creatinine levels[73] due to creatine ethyl ester being converted into creatinine via non-enzymatic means in an environment similar to the digestive tract.[74][75] At equal doses to creatine monohydrate, ethyl ester has failed to increase water weight after 28 days of administration (indicative of muscle deposition rates of creatine, which are seemingly absent with ethyl ester).[76] 
Furthermore, because creatine can help restore ATP levels, increasing energy, it can lead to reduced amounts of heart muscle stress. More energy in your life will result in less pain, stress, and boost morale in everyday life which has a significant role in improving heart health. The increased capacity to exercise is also crucial in maintaining and improving heart health.
Creatine ethyl ester is more a pronutrient for creatinine rather than creatine,[74] and was originally created in an attempt to bypass the creatine transporter. It is currently being studied for its potential as a treatment for situations in which there is a lack of creatine transporters (alongside cyclocreatine as another possible example).[77] Its efficacy may rely on intravenous administration, however.
Heart Failure is one of the single most common complications that face many people today. When a heart ages, the cells collect a yellow-brown layer which is waste and can lead to heart complications. This process is known as lipofuscin, or “aging pigment” which leads to death opposed to someone who can delay that as far as possible. [3] In mice, a study was performed where two groups of mice who had lipofuscin underwent different experiments, one group received creatine supplementation, and one group did not receive supplementation. What they found was that the mice who supplemented creatine lived 9% longer than the ones who did not receive creatine. 9% translated into human years results in almost 7 years, which could suggest that if you suffer from this deterioration, creatine supplementation could potentially increase your longevity by 7 years. [3]
If you’re a beginner, you should train with three full-body workouts per week. In each one, do a compound pushing movement (like a bench press), a compound pulling movement (like a chinup), and a compound lower-body exercise (squat, trap-bar deadlift, for example). If you want to add in 1–2 other exercises like loaded carries or kettlebell swings as a finisher, that’s fine, but three exercises is enough to work the whole body.
The neuroprotective effects of creatine appear to exist in regard to dopamine biosynthesis, and the suppression of dopamine synthesis seen with some neurological toxins appears to be partially attenuated with dietary intake of creatine. The protective effect is weak to moderate in animal research, but appears to be additive with anti-inflammatories.
Listen, I know in the beginning of this post I was sympathetic to your problem, but I am also here to say, Suck It Up. I can tell you that to gain weight, you need to focus on making your meals a habit rather than an afterthought. Your body is pre-programmed with your genetic disposition. And in your case, you have a very fast metabolism that digests and burns calories quickly. Focus on having 5-6 calorie-dense meals a day spaced 2-3 hours apart so that your body is constantly being provided with something to metabolize and build muscle.

However, in the beginning weeks of starting a new workout routine, the majority of strength gains aren't actually a result of this muscle protein synthesis and hypertrophy. Rather, they are a result of the body's neurological system learning when and how to fire the needed muscle cells, explains Abbie E. Smith-Ryan, associate professor of exercise physiology at the department of exercise and sport science at the University of North Carolina–Chapel Hill. Think of it this way: The first time you perform a new exercise, say a bench press, you likely feel pretty shaky. Your arms aren't totally in sync and the weights may sway a bit from side to side. But by the time you perform your second or third set of that same exercise, the practice gets a little smoother. That's your neurological system at work.
Research shows that strength training is especially effective at raising EPOC. That’s because, generally speaking, strength-training sessions cause more physiological stress to the body compared to cardiovascular exercise, even higher-intensity cardio intervals. However, it’s worth noting that overall exercise intensity is what makes the biggest impact on EPOC. So squats, deadlifts, and bench presses with heavy weights are going to be much more effective at raising EPOC compared to bicep curls and triceps extensions with light weights.